Field
The present disclosure relates to systems and methods for computed tomography (CT) angiography procedures, and more particularly, to a system and method for a low dose CT perfusion technique for routine functional assessment of coronary artery disease.
Description of the Related Art
Coronary heart disease is the leading cause of death and morbidity worldwide. Currently the most-used noninvasive method for visualizing coronary atherosclerosis is coronary computed tomographic (CT) angiography. Although the method's image quality has improved greatly over the last decade, previous CT angiography studies have often overestimated stenosis severity. Furthermore, it is difficult to reliably assess the severity of a stenosis in the presence of coronary artery calcification. It is also difficult to determine stenosis severity when assessing intermediate coronary lesions (30%-70% diameter stenosis), where angiography has only limited ability to distinguish ischemia-producing from non-ischemia-producing obstructions.
Conventional semi-quantitative myocardial perfusion imaging, such as single-photon emission computed tomography (SPECT), is commonly used for functional assessment of these coronary lesions. However, these techniques only estimate relative perfusion, which is limited in its ability to identify the extent of multivessel coronary artery disease burden and balanced 3-vessel coronary artery disease. Dynamic myocardial perfusion in absolute terms (ml/min/g) is possible using positron emission tomography (PET), which extends the scope of conventional semi-quantitative myocardial perfusion imaging. However, myocardial perfusion with PET is limited by access to necessary radiolabeled tracers, radiation dose, and cost.
CT perfusion techniques to provide functional assessment of stenosis severity. However, widespread clinical implementation of such techniques has been hampered by the fact that these techniques generally underestimate the actual myocardial perfusion and deliver a very high radiation dose to the patient.